Toward a Digital Music Theory: Opelt’s Siren and the Technologies of Musical Hearing

Toward a Digital Music Theory: Opelt’s Siren and the Technologies of Musical Hearing

Alexander Rehding

Opelt Siren—cardboard model produced by Rudolf Koenig, from Harvard University’s Collection of Historical Scientific Instruments.

Opelt Siren—cardboard model produced by Rudolf Koenig, from Harvard University’s Collection of Historical Scientific Instruments.

Opelt Siren—cardboard model produced by Rudolf Koenig, from Harvard University’s Collection of Historical Scientific Instruments.

Unbeknown to most people, in 1834, a tax collector, hobby astronomer, and musician proposed a revolutionary music theory that promoted digital principles of sound production. Friedrich Wilhelm Opelt (1794–1863) may be the most important music theorist you have never heard of. Given that music theory is working hard to catch up with developments in musical production of the last thirty years, it is quite possible that Opelt’s moment in the sun has finally come.

Opelt’s theory made use of a recent invention, Charles Caignard de la Tour’s mechanical siren (1819), which he expanded and improved. Caignard’s model consists of a metal disk with holes in regular intervals which, when set in rotation and with air blown through them, produce a series of air puffs. Once their pulsation is faster than 20Hz, this pulse will be heard as a continuous, rising pitch. Opelt’s experiments showed that more complex patterns of holes translate into intervals, chords, and harmonies. Opelt demonstrated that every pitch event can be translated into a corresponding rhythmic event. Pitch and rhythm may be different perceptual parameters, but physically, they are both events of temporality, which merely inhabit different dimensions of the time axis.

Opelt’s ideas about the close correlation of musical parameters was overdetermined. To date, no piece of music exists that actually fully puts his principles in place (though Henry Cowell’s youthful Quartet Romantic of 1915 comes close). But Opelt’s ideas constitute the first rigorous formulation of a principle that rose to some prominence in various branches of twentieth-century music.